Printing telegraph system



Nov. 19, 1935. A, H. REIBER El AL 2,021,383

PRINTING TELEGRAPH SYSTEM Filed Aug. 30, 1.934

INVENTORS ALBEPT ff Q5/5512 WALTER J.ZE/V/VBQ ATTORN III Patented Nov. 19, 1935 UNITED STATES PATENT oFFicE PRINTING TELEGRAPH SYSTEM Delaware Application August 30, 1934, Serial No. 742,066

16 Claims.

This invention pertains to telegraph systems and more particularly to printing telegraph receiving circuits and apparatus.

The principal object of the invention resides in the provision of a receiving printer arranged to be non-responsive under certain conditions of operation.

An important feature of the invention consists in the provision of means to maintain mechanically the selector magnet armature of the printer in stop or marking position during non-signalling periods when it would otherwise tend to assume its spacing or starting position resulting in the recording or" false signals.

Another feature of the invention resides in the provision of a centrifugally controlled means associated with the motor for preventing the operation of the printing apparatus unless the motor has attained its operating speed, and which, in cooperation with an auxiliary magnet adapted to control the action of the selector magnet, positively prevents the printing of false characters.

The present invention contemplates the provision of a single magnet selector mechanism responsive to code combinations of signalling impulses, wherein there is associated with the selector magnet a selector lever comprising an armature and an armature extension. The aforementioned and other objects of the invention are accomplished by the association with said selector magnet of an auxiliary magnet having its armature so arranged as to act, under predetermined conditions, upon the selector armature extension to hold the latter in its stop or marking position. In one form of the invention the armature of the auxiliary or anti-spin magnet (so called from the fact that it functions to prevent the selector lever, due to an open line or prolonged spacing condition, from releasing the selector cam member for continuous rotation and consequent false printing) is adapted to latch mechanically the selector lever in its stop or marking position. In another form of the invention the armature of the anti-spin magnet is provided with a spring which is so chosen as to overpower the selector lever spring, in which event, upon the simultaneous deenergization of the selector and anti-spin magnets, the armature of the latter magnet will act to maintain, due to its greater biasing efiect, the selector lever in its stop or marking position.

Moreover, upon the printer motor shaft is carried a centrifugal device which'functions to control a contact assembly which, in turn, serves to control certain of the printer circuits, among which are the selector magnet and anti-spin magnet circuits, so as to render the printing apparatus effective only when the motor has attained its normal operating speed and thereby, in 5 conjunction with the anti-spin magnet, preclude the'possibility of printing false characters.

A better understanding of the invention may be had from the following description, taken in conjunction With the wherein,

Fig. 1 is a fragmentary plan view of a selector mechanism of the swordand T-type, controlled by a neutral magnet, with portions omitted or broken away to reveal the essential operating 5 members in which the present invention is embodied;

Fig. 2 is a sectional view taken substantially on line 2-2 of Fig. 1;

Fig. 3 is a simplified circuit diagram illustrat- 2 ing the application of the present invention;

Fig. 4 is a View partially in section of the centrifugal device according to the present invention;

Fig. 5 is a front elevation similar to Fig. 1 of 25 a selector mechanism showing an alternate arrangement of the present invention;

Fig. 6 is a sectional view taken on line ii6 of Fig. 5, and

Fig. 7 is a circuit diagram showing one method 30 of delaying the release of the selector magnet until the anti-spin magnet of the present invention has been previously released.

Having reference to the accompanying drawing in which like reference characters indicate 35 similar parts throughout, the selector mechanism illustrated in Fig. l is similar to that which is used commercially in several standard types of printing telegraph machines. The selector mechanism disclosed is shown only in sufficient detail to enable an understanding of the present invention. For a complete understanding'of details not disclosed herein and which form no part of the present invention, reference may be had to Patent No. 1,745,633 to S. Morton et al., which shows printing telegraph transmitting and receiving apparatus to which the present structure is particularly applicable. I

This mechanism comprises a set of six (or five, depending .on the code adopted) selector elements in the form of thin, flat fingers or swords ll arranged in superimposed relation between guide plates I 2. These plates are mounted on studs l3 and spaced by washers not shown. The circular rear ends I4 of the fingers H engage accompanying drawin 10.

corresponding sockets P5 in six thin, fiat bell cranks l6, pivoted on a common shaft l1. Individual springs l8 normally hold the bell cranks l6 and selector fingers i in the positions shown in Figs. 1 and 5 with the pointed end |9 of the bell crank IS in contact with a selector cam barrel 2| on shaft 22 which is driven continuously by a properly regulated motor, the driving connection between the shaft 22 and the cam barrel 2| being established through friction clutches, one of which is indicated at Zil (Fig. 2)

The cam barrel 2| is provided with .a helically arranged series of cams 25, one for each of the bell cranks H3, which rotate the bell cranks it in succession and thus reciprocate longitudinally the corresponding series of selector fingers l as the cam barrel 2| is rotated. In addition to the longitudinal movement, the selector fingers if have a lateral swinging movement between the pair of studs 26.

The setting of any selector finger either to its dotted-line or solid-line position (as indicated in Fig. l) is determined by the selector electromagnet 21 which is mounted on a bracket 28 in the printing apparatus. The armature 23 is carried by a lever 3| which is pivoted on a shaft 32 supported in the frame of the apparatus. The unit comprising lever 3| and armature 29 is maintained, when the line circuit is closed and magnet 22 is accordingly energized, in the position shown in Fig. 1, against the action of a spring 38, the tension of which may be adjusted by an adjusting screw 39. Lever 3| terminates in a U-shaped portion 35, having downward extending arms 33 which constitute abutments which cooperate with arms 3? on the rear ends of the swords or selector fingers i, and act toposition the latter in either the dottedline or solid-line position. That is, the distance between the depending portions 36 of lever 3| is somewhat less than the distance between each cooperating pair of lugs 31, so that when either of the portions 36 is disposed to register opposite its cooperating lugs 37, the other of the two portions 33 falls short of engagement with its cooperating lug 37. As may be seen from Fig. 1, spring 38 tends to maintain lever 3| so that one of its portions 36 registers opposite its associated lug 31 while magnet 21, upon energization, operates to maintain it so that the other of its depending portions 36 registers opposite its associated lug 31. In other words, the energization of magnet 21 causes the presentment of lever 31'! in one position to cooperate with one of the abutments of the swords while its deenergization causes its presentment in the other position to cooperate with the other of the pair of lugs 31.

The selector fingers act through a corresponding number of T-shaped levers 45 arranged between the guide plates I2 and pivotally mounted on a stud 42, to position a set of code elements which are not shown but are exemplified by the fragment 43 and are capable of being moved into one or the other of two positions. To each element 43 is articulated one arm of T-lever 6!. As indicated T-levers 6| are provided with two symmetrical and oppositely disposed extensions which coact with the end of their individual selector fingers so that the T-lever 4| is rocked in conformance with the selected position of selector finger H to actuate in turn its associated element &3 correspondingly.

A magnet 45 supported by bracket M5 cooperates with an armature 41, the remote end of which is notched at 48 (Fig. 2) and is located so as to receive within its notch 43 a narrow portion 49 of selector lever 3|. As previously indicated, magnet 45 is herein known as the antispin magnet, in accordance with the present invention. Each magnet 21 and 45 has its own energization control switch, as will hereinafter appear, so that when line relay 5| (Fig. 3) receives a current condition from the signal line in accordance with the prevailing practice, magnet 21 is energized by the movement or" the armature 52 which closes a circuit to energize selector magnet 2?.

The anti-spin magnet 43 is energized at such times when the station is in communicative condition, while it is deenergized at other times, and because armature 41 is effective only during the vdeenergized condition of its. magnet 35 and is ineffective during the energized condition thereof, it will restrain selector lever Si in marking position, except when the receiving mechanism is in communicative condition.

Referring further to Figs. 1 and 2, it is noted that the selector lever 3| is provided with a projection 53 terminating in an eccentric adjustment screw 54%, the function of which is to initiate through a series of levers the rotation of the selector cam barrel 2! in a manner clearly set forth in Patent No. 1,745,633. Briefly, however, for the purpose of the present disclosure, this arrangement has been partially shown in Fig. 2 wherein the adjustable screw 54 coacts with a plunger 55 carried in support 55 which actuates a small bell crank 51, pivoted at 58 in support 56,

to rock a latch member 59, pivoted at 65 to support 52, mounted on an orientation plate 53. Latch 5% is normally urged by a spring 66 into locking engagement with a stop member 65 pivoted on a stud 66 secured to plate 63. Stop 55 is of U-shaped conformation, the lower .arm of which cooperates with stop disc 3? to arrest the rotation of selector cam barrel 2.5.

In operation, upon the receipt of a spacing or start signal, the selector magnet 21 becomes deenergized and armature lever 3| is actuated by its spring 38 in a clockwise direction (as viewed in Fig. 1), thus carrying the adjusting screw 54 therewith. This movement of the selector lever 3| through screw 54 acts to move plunger 55 to rotate, in turn, bell crank E? in a counterclockwise direction (as viewed in Fig. 2) to rock latch 59 rightwardly against the urge of spring M to unlatch member 59 from stop arm 65. Since the stop disc 151 is subjected to a constant torque due to its frictional connection with constantly rotating shaft 22, but is held from rotation by the stop arm 65, it will, upon the unlatching of member 59 on stop arm 65, cause stop arm to ro-. tate about stud 6'5 until it is free of said stop arm, whereupon the stop arm 65 will again return to its normal position by the action of a spring, not shown, into latching engagement with member 553 so that when stop disc 6? has completed one revolution it will again coact with stop arm 65 which, being restrained by latch member 59, will arrest the rotation of stop disc 61 and hence selector cam drum 2|.

An alternate form of anti-spin arrangement is illustrated in Figs. 5 and 6, in which a blocking type of anti-spin device is provided for holding a selector lever 3| against actuation, instead of the latching type as shown in Figs. 1 and 3. In this embodiment the antl-spin magnet I28 is substituted for the corresponding magnet :15 of Fig. 1, the support I29 therefor being disposed as indicated in Fig. 5. The armature I3I of antispin magnet I28 is pivoted at I32 and is provided at its opposite extremity with a depending pin I33 which serves, when magnet I28 is deenergized, and armature I3I is rotated clockwise by its spring I34, to block or restrain selector lever 3| in its counterclockwise position, the spring I34 being stronger and thereby adapted to overpower spring 38.

Referring now to the circuit diagram shown in Fig. 3, the broken-line square indicated generally as H represents the printer and the rectangle indicated generally as I2 represents the control box therefor at a subscribers station. Electrically, the anti-spin device consists primarily of an electromagnet and centrifugally operated contacts which function to prevent the false operation of the receiving printer when the motor is first connected to the line; that is, before it has attained its normal operating speed, and also when the motor is' being stopped. The centrifugal switching device shown in Fig. 4 and indicated generally as 13 in Fig. 3 consists of a rotor M mounted on the motor pinion I5 and a contact assembly indicated generally as It mounted on the base of the printer. The rotor contains a pair of weights 'I'I pivoted on individual pivots I8, which move away from the axis of rotation as the motor accelerates. The centrifugal or outward motion of these weights acts through arms I9 and disc 8| to compress a spring 82 and allow the contact assembly It under its own spring action to change its position. When the motor stops, the reverse or original condition again exists and the compression spring 32 returns the,

contact assembly to its right-hand position (as viewed in Fig. 3).

The contact assembly I6 consists of make-break or transfer contacts 83B I-and a make contact 85. Included also in the energizing circuit for the anti-spin magnet 45 is a contact 36 which is one of a pair of contacts controlled by a pull bar ill in the printing apparatus, the other contact 83 of said pair is included in the energizing circuit for the circuit-breaker magnet 89 of the motor control unit indicated generally as 9!.

The relation between the armatures of the selector and anti-spin magnets may be either as shown in the preferred embodiment in Figs. 1 and 2 or as in the modification shown in Figs. 5 and 6. In the preferred form the armature M of the antispin magnet acts, under certain predetermined conditions, to latch the armature lever SI in its operated or marking position, thus preventing,

' upon a cessation of signalling, the release of the selector cam member 25 for continuous rotation,

and consequently, the printing of false characters.

A similar effect is obtained by the embodiment shown in Figs. 5 and 6, but in this instance the armature lever 3i is maintained, upon the simultaneous deenergization of both the selector and anti-spin magnets, in its marking position by reason of the fact that spring I34 for armature I3I is so chosen as to overpower the selector armature spring 38. In the circuit diagram in Fig. 3, the principle embodied in Figs. 5 and 6 has been adopted since that modification lends itself more readily to a schematic showing thereof; but it is, of course, understood that the principle embodied in Figs. 1 and 2 is equally adaptable.

Under normal conditions when a subscribers station circuit is not connected for communication, a circuit may be traced from the ring side R (Fig. 3) of the transmission line extending from the subscribers premises to the central ofiice through a condenser 95 and bell ringer 96 through contact 91 of a flash or recall key 94, over conductor 98, through contact 84 of the centrifugally controlled switching device I3, over conductor 99 to ground. This ground is also normally connected to the tip side T of the transmission line over a path traced from T through the winding of polarized relay 5I, through polarized relay IGI, contact 91 of recall key 94, conductor 98, contact 84 of the centrifugal switching device '63, conductor 99 to ground. As will' hereinafter appear. relay I BI is operated by means of current supplied through the tip side of the line only. The circuit hereinbefore traced from the ring side R of the line through the bell ringer to ground permits the operation of this bell ringer to attract the attention of the subscriber at the station when ringing current is transmitted over the ring side R of the line from the central office. As will also appear hereinafter, the circuit from the tip side T of the line through relays 5! and HM to ground is provided to enable the motor to be started from the central ofiice in the event that the subscribers station is unattended.

The operator at the sub-scribers station, in response to the ringing of the bell 96, answers the call by manually closing contact I92 (commonly designated as the answer key), the effect of which is to establish an energizing circuit for motor control magnet I93 from source of current, through the magnet I93, over conductor EM, through contact I92 (now closed momentarily) over conductor I95 to ground. The energization of magnet I93 causes the armature I 96 to pull up, thereby unlatching contact assembly I9I to close simultaneously circuit-breaker I62 and contact I99. Current then flows from source of alternating current (or direct current if preferred), through circuit-breaker contact I98, over conductor III, through motor IIZ, to ground, thus starting the motor II2 into operation. At the same time, a circuit is completed from said source through circuit-breaker contact I98, over condutor I I3, through rectifier 59, over conductor we to ground, thereby operating the rectifier 59 to produce direct current for local use.

As the motor IIZ accelerates, it operates the centrifugal switching device it to effect, upon reaching normal speed, a change in the contact assembly It, such that contacts 83 and 85 (formerly open) will now be closed, and contact i i (formerly closed) will now be open. The opening of contact 84 breaks the ground circuit for magnet ItI, thereby causing it to deenergize, and also breaking the bell ringer circuit over the ring side R, of the line. moves ground from the tip side T of the line and connects, through the closing of contact 83, the T and R leads of the line from the central oflice through the subscribers stations set. Included in this last mentioned circuit are the sending con- I tacts H t and the break contact N5 of the subscribers transmitting set.

' The closing of contact 85 establishes an energizing circuit for the anti-spin magnet I28 from source of current, which may be from the positive terminal of rectifier 59 (now operated), over conductor I I6, through contacts 85 and 8%, over conductor I I1, through winding of magnet I28, over conductors I I8and I I9 to opposite terminal of said source of current. Upon energization of magnet I28, its armature I3I is operated, thus removing the restraint from armature 3| of selector magnet 27 which latter magnet and armature are now free tooperate in response to selective signal im- Moreover, opening contact 84 re pulses. During signal intervals the anti-spin magnet [28, being of the slow release type, remains energized over the last mentioned circuit, due to the fact that the time between signal impulses is not of sulhcient duration to permit the magnet i223 to release its armature.

The'subscribers station is now in condition for transmission or reception of signals. The transmission of signals is effected, as is well known, through a keyboard sending device which operates the sending contacts lid permutably to transmit permutation code signals over the ring side R of the line. The reception of signals is eiiectuated upon the selective operation of relay 5! in accordance with received signals over the loop circuit T to R, and the corresponding selective operation of armature 52, which upon the reception of each marking impulse will establish an energizing circuit for selector magnet 21 from source of current (for example, the positive terminal of rectifier 5E5), over armature 52, through contact 623, over conductor I24 through winding of selector magnet 22", over conductor MS to the opposite terminal of said source of current. Incidentally, polarized magnet ml, which operates only when reversed current is applied from the tipside T of the line, will not respond to signalling current nor, of course, signalling impulses.

Assuming, again, that the station (Fig. 3) is in its original uncperated condition, and that it is desired to initiate a call from the subscribers station, the operator thereat closes the manually operable contact l2l (commonly known as the call key), the effect or" which will be the same as that just described in response to the closing contact Hi2.

In the event that the subscribers station is unattended, the central oflice may start the unattended printer thereat, thus permitting the calling subscriber to transmit a message to the unattended station. This may done by applying battery opposite in polarity to signalling battery to the tip side T of the line at the central omce, which current will operate the polar relay t l at the subscribers station. The circuit extends from the tip side T of the line through the windings of relays iii and then through contact El, over conductor 98, through contact 86, over conductor 39 to ground, thus operating relay liii to close its contact I22. The closing of contact 422 will complete a circuit from ground, over conductor ifiii, through contact 22, over conductor lo l, through motor control magnet 33 to source of current as, for example, the supply of alternating current. The subsequent operaticns, that is, the operation of motor control unit 9i, motor IE2, centrifugal switching device l3, and anti-spin magnet are wiil be effected in the same manner as previously described in connection with the closure of contact Hi2.

Simultaneously, however, with the energization or" relay ids and the ensuing preparation of the receiving printer for operation, the polar relay 5! will also, as previously indicated, efiect the operation of its in response to signal impulses which, for marking impulses, will close contact 523, establishing an energizing circuit during marking intervals from source of current (for example, rectifier over armature 52,

through contact over conductor through selector magnet over conductor M9 to opposite terminal of said source of current. In relector mechanism shown in Fig. 1,, the setting of members 43 in accordance with the received code combination of signalling impulses. At the completion of the transmission of messages to the subscribers station, the central operator can stop the motor at the subscriber'is station at will upon the transmission thereto of a motor stop signal which,in the system according to the present disclosure, is the signal for upper case H. Upon reception of said motor stop signal by the printing apparatus 5 l, a pull bar El is actuated in wellknown manner to operate in turn the contacts and 38, whereby contact 8% is opened and contact 88 is closed, momentarily. The opening of contact 86 breaks the energizing circuit for the antispin magnet 28, thus causing its deenergization and the consequent release of armature it! by means of spring I35. In this condition, the armature l3l restrains armature 3| so that even if signals are received by the selector magnet 21 they will have no effect upon the selector mechanism, since armature 31 is constrained by armature 13! against selective operation. Thus, since the magnet !23 is deenergized upon receipt of the motor stop signal, it is manifest that the selector magnet 22? will promptly become ineffective, thereby preventing the printing of false characters during the retardation of the motor in stopping.

The closing of contact 88 establishes an energizing circuit for magnet 89 of the motor control unit 9| from source of current (for example, the A. C. supply), through contact Hi9, thence through the winding of magnet so, through contact 8?, to ground. The cnergization of magnet 85 causes the contact assembly ml to operate to become locked in its operated position by latch 86 associated with magnet H33. Thereupon, the circuit breaker contact lot is opened, the efiect of which is to open the circuit for motor E E2, thus causing the latter to stop, at the same time shutting off the alternating current supply to the rectifier 55]. The release of the anti-spin magnet I28 precedes the release of the selector magnet 27 by a time period equal to the attracting time of the circuit breaker contact assembly it! associated with magnet 89 and assures proper coaction between armatures 3i and i311, and if the preferred form shown in Figs. 1 and 2 is used, it

assures proper latching of the armature 3i of the selector magnet 21' by the latch 41. The time period may be varied by changing the adjustment of the upper case l-I contacts, the magnet 89 remaining energized over a circuit through current reducing resistance 525 so long as contacts 88 remain closed.

retardation of the motor before stopping will cause the centrifugal switching device it! to operate the contact assembly iii to open contacts 33 and 85 and close contact as, thus placing the receiving circuit in the condition shown in Fig. 3. Assuming, now, that the station is in operation, means is provided comprising a manually operated emergency contact 312% to interrupt the reception of messages and to place the circuit at the receiving station in a non-operative position. This is effected by closing contact lZE to establish an energizing circuit for the circuit-breaker magnet to of the motor control unit 9E from ground, over conductor :35, through contact Hi6, over conductor i227, through the winding of magnet 88, through contact 1&9 (and subsequently resistor I25) to source of current. This operation will cause the motor control unit to function to stop the motor H2 and out off the supply of alternating current to the rectifier 50, thereby preventing the receiving printer from operating in response to received signals.

There is shown in Fig. 7 an electrical means for delaying the release of the selector magnet 2'! to insure the release of the anti-spin magnet prior to the selector magnet to effect the latching of armature 41. This method consists in providing an electrostatic condenser in parallel with the selector magnet of the printer for maintaining the magnet energized until the driving motor has stopped and thus preventing, through the prior deenergization of the looking or anti-spin magnet, the printing of false characters.

As indicated diagrammatically in Fig. 7, the anti-spin magnet 45, motor H2, and rectifier 50 are connected in parallel in a circuit connected to a local source of alternating current. In this circuit is also a motor control contact or power switch I35 controlled by the printer mechanism. Connected in parallel to the direct current output of the rectifier 58 are an electrostatic condenser I3ii and the selector magnet 21. Also in this circuit and in series with the selector magnet is a receivingrelay l3? connected to the signal line I38.

Assuming that the receiving station is in op eration, the motor control contacts I35 will be closed, the motor I 12 will be running and the anti-spin magnet 45 will be energized, thus attracting its armature to remove the restraint thereof from the selector lever of the selector magnet 21. Upon the closure of contacts Hi5 alternating current will flow through the rectifier 50, thus generating direct current which will be supplied continuously to the condenser iSG, and intermittently to selector magnet 2'! in accordance with the selective oscillations of the armature of the line relay l3l, in response to line signals. Now, upon receipt of the motor stop signal, the motor control contacts I35 will be opened, for example, in the manner heretofore described in connection with pull bar 81 in Fig. 3, thus cutting oif the supply of alternating current from the motor 5 i2, anti-spin magnet 45, and rectifier 5!). The selector magnet 21 obviously will no longer receive current from the rectifier 5i], but due to the deenergization of rectifier 553, the condenser I36 will discharge its supply of current to the selector magnet 21 for a predetermined interval of time which is controlled by the resistor B39. Thus it is seen that the condenser !36, bridged or shunted across the selector magnet, will sustain the power supply to the selector magnet 27, thereby preventing the premature release thereof before the release of the anti-spin magnet 45. Therefore, the antispin magnet 45, being enabled to deenergize before the selector magnet 21, will effect the release of its armature ll to latch the selector lever 3! to prevent the false operation of the printer.

It is, of course, understood that this application is intended to cover not only the specific embodiments herein disclosed, but also such changes or modifications as come within the spirit of the invention or the scope of the following claims.

What is claimed is:

1. In a control system for printing telegraph receivers comprising a selector magnet, means effective for allowing free movement of the armature of the selector magnet during signalling periods, and means controlled by the telegraph receiver for controlling said means to cause the mechanical locking of the armature of the selector magnet.

2. In a control system for printing telegraph the deenergization of said electromagnet to effeet through the release of its armature the mechanical locking of the armature lever of the selecting magnet.

3. In a control system for printing telegraph apparatus, receiver mechanism, a selecting magnet having an armature responsive to line signals, an electromagnet normally energized during reception of line signals having an armature arranged in cooperative relationship with said first recited armature, said last recited armature having a notch effective when said last recited armature assumes one of its positions for constraining said first recited armature, and contacts controlled by the receiver mechanism for causing the deenergization of said electromagnet to effect the application of constraint to said first recited magnet.

4. A printing telegraph system comprising a line circuit, a printing telegraph receiving and transmitting mechanism connected to said line means associated with said motor for rendering said) alarm mechanism non-effective, and effective simultaneously for removing the restraint of said first mentioned means on said printer mechanism.

5. A printing telegraph system comprising a transmitting and receiving mechanism, a motor for driving said mechanism, motor control means operating with said mechanism for starting and stopping said motor, anti-spin means cooperative with and adapted to control the effective operaion of said mechanism, and a line circuit connected to said mechanism, a selective operation of said mechanism in response to line signals being effective to control simultaneously said antispin means and said motor.

6. A control system for printing telegraph receivers having a selector magnet and comprising an electromagnet energized during normal signalling periods for allowing free movement of the armature of the selecting magnet of the printer, a driving motor, and an operating circuit therefor, and an electrostatic condenser in parallel with the selector magnet of the printer effective upon the breaking of said circuit for maintaining the selector magnet energized until the driving motor has stopped and thus prevent, through the prior deenergization of said electromagnet, the

printing of false characters.

7. In combination, a constantly rotating member, a member to be driven by said constantly rotating member, a frictional connection between I the two members, means comprising a plurality of pivotally mounted members for locking the second mentioned member against rotation, means operative under certain operating conditions for initiating the rotation of said second recited member, and means operativeunder other operating conditions for preventing the operation of said initiating means.

8. In combination, a constantly rotating member, a member to be driven by said constantly rotating member, a frictional connection between the two members, means comprising a plurality of pivotally mounted members for locking the second recited member against rotation, means operative under certain operating conditions for initiating, through said plurality of pivotally mounted members, the rotation of said second recited member, and means operative under other operating conditions for preventing the operation of said initiating means.

9; In combination, a constantly rotating. member, a member to be driven by said constantly rotating member, a frictional connection between the two members, means comprising a plurality of pivotally mounted members for locking the second recited member against rotation, means operative under certain operating conditions for initiating, through said plurality of pivotally mounted members, the rotation of said second recited member, and electromagnetic means comprising a notched armature for preventing, under predetermined conditions, the operation of said initiating means.

10. In combination, a constantly rotating member, a member to be driven by said constantly rotating member, a, frictional connection between the two members, means comprising a plurality of 'pivotally mounted members for looking the second recited member against rotation, means operative under. certain operating conditions for initiating, through said plurality of pivotally mounted members, the rotation, of said second recited member, means for preventing the operation of said first recited means, and unbalanced. spring means operative under other operating conditions to render said last recited means effective to prevent the operation of said initiating means.

11. In a control system for printing telegraph receivers having a selector magnet and comprising an electromagnet energized during normal signalling periods for allowing free movement of the armature of the selector magnet of the,

. printer, a driving motor, and an operating cir- 01111;, a rectifier and an anti-spin electromagnet connected in parallel in said circuit, operating contacts selectively controlled by the printing mechanism, and a direct current circuit derived from said rectifier including an electrostatic condenser and a selector magnet for said printing mechanism connected in parallel, said electrostatic condenser adapted upon the selective operation of said contacts for maintaining said selector magnet energized for a predetermined time to insure the prior deenergization of the anti-spin electromagnet.

13. In a control system for printing telegraph receivers, a selector magnet, an armature lever therefor, an electromagnet energized during normal signalling periods having its armature opera-ted during said periods to allow free movement of said armature lever, contacts controlled by mechanism of the receiver for causing the deenergization of said electromagnet to effect through the release of its armature the mechanical locking of said armature lever, and an energy-storing device for maintaining the energization of said selector magnet to insure the prior deenergization of said electromagnet.

14. A printing telegraph system comprising a transmitting and receiving mechanism, a motor for driving said mechanism, motor control means operating. with said mechanism for starting and stopping said motor, centrifugally operated contacts controlled by said motor, anti-spin means cooperative with and adapted to control the effective operation of said mechanism, and a line circuit connected to said mechanism and said centrifugally operated contacts, a selective operation of said mechanism in response to line signals being effective to control said anti-spin means and simultaneously, through said motor, said centrifugally operated contacts.

15. In a. control system for printing telegraph receivers comprising a selector magnet, an electromagnet energized during normal signalling periods for allowing free movement of the armature of the selector magnet during signalling periods, and contacts controlled by the telegraph receiver for causing the deenergization of the electromagnet and the mechanical locking of the armature of the selector magnet.

16. In a control system for printing telegraph receivers comprising a signal responsive means, means efiective for allowing free operation of said means during signalling periods, and means controlled by the telegraph receiver to render said signal responsive means inefiective.

ALBERT H. REIBER. WALTER J. ZENNER. 

